It is common practice to inductively heat an article (e.g., a solid cylinder or hollow tube) of a magnetizable material, such as steel, by inducing an eddy current in the article. This eddy current is induced by an applied magnetic flux generated by passage of an alternating current through a heater coil wound around the article. The heat inductively generated in the article may then be transmitted to another article, e.g., a metal or polymer material flowing through a bore or channel of an inductively heated steel tube.
Various systems have been proposed which utilize different combinations of materials, structural heating elements, resonant frequencies, etc., for such heating techniques. There is an ongoing need for an apparatus and method for heating a material in a channel which provides one or more of higher power density, tighter temperature control, reduced power consumption, longer operating life, and/or lower manufacturing costs.